摘要
为了消除基于面阵探测器的锥束X射线计算机断层成像(XCT,X-ray Computed Tomography)检测系统中探测器的安装误差对重建断层图像的影响,使投影坐标系准确建立,并与重建坐标系精确配准,提出了基于椭圆拟合的平板探测器位姿参数的估计方法.并在此基础上,从锥束XCT的近似重建算法FDK(Feldkamp)出发,结合空间坐标变换原理,改进了重建算法中投影地址的计算方式,使之能在存在安装误差的情况下准确计算投影地址,重建出正确的断层图像.该方法简单有效,计算量小,无需对系统硬件进行调整.实验结果表明,利用该方法可以有效地消除由于探测器位姿引起的图像伪影.
To eliminate the artifacts in computed tomography（CT） images caused by the flat plane detector（FPD） pose error in cone-beam X-ray CT（XCT） testing system,methods of error measurement and correction were proposed.The ellipse fitting method based on the least squares technique was used to get the detector pose error which is essential for projection coordinate establishing and matching with the reconstruction coordinate accurately.The correction method improves the original Feldkamp（FDK） reconstruction algorithm in the calculation of projection address based on the spatial coordinate transformation theory by which the projection address could be calculated correctly.The methods are of less computation consuming and without hardware calibration.The experimental result proves that the methods could eliminate the artifacts effectively and help reconstruct CT image with high accuracy.
出处
《北京航空航天大学学报》
EI
CAS
CSCD
北大核心
2012年第12期1657-1660,共4页
Journal of Beijing University of Aeronautics and Astronautics
基金
国家自然科学基金资助项目(60872080
61077011)
多相复杂系统国家重点实验室开放课题资助项目(MPCS-2011-D-03)
国家科技支撑资助项目(2011BAI02B02)
关键词
锥束扫描
探测器位姿
椭圆拟合
FDK重建算法
cone-beam scanning
detector pose
ellipse fitting
FDK reconstruction algorithm
